robert muller at harvard's beth israel deaconess medical center has devoted more than 40 years to studying them. why do you love these bugs so much? >> they're among the most interesting things that we can study. >> reporter: what he finds interesting many people find terrifying. that's because super bugs are extraordinarily resilient bacteria. they tend to infect hospital patients and even kill those who are extremely ill. the most recent study on health care associated infections in u.s. hospitals found that out of about 1.7 million infections, nearly 99,000 patients die. according to one of the study's authors, the vast majority of the deaths were due to super bugs. are some super bugs resistant to all the antibiotics that we have at our disposal? >> a few of them are literally resistant to everything. fortunately these are the exceptions rather than the rule. but the fact that we have any of these at all is cause for alarm because the only thing we can say is we're to see more of these as time goes on. >> reporter: super bugs can enter a patient through surgical wounds and catheters in